To drive a typical car at 40 mph on a level road for one hour requires about 3.2 × 10^7 J of energy. Suppose we tried to store this much energy in a spinning, solid, uniform, cylindrical flywheel. A large flywheel cannot be spun too fast or it will fracture. If we used a flywheel of diameter 0.628 m and mass 338.9 kg, what angular speed would be required to store 3.2 × 10^7 J? Give your answer in rad/s.